I have a 93 Corvette that will not start. Diagnostic code indicated that Pass-key not detected. Replaced keys at GM dealership. No change. Confirmed resistance on key, it is correct. Changed tumbler. No help. I tried the Radio Shack resistor by-pass. No help.

I have checked all grounds, numerous times. I have checked all fuses, numberous times. I have checked all connections, numerous times. The car has not started for over 1 year. I have jumped the starter relay pins and the car will crank by doing this. I have come to the conclusion that the ECM or CCM is bad. Not sure which one but betting on the CCM.

I have purchased a by pass module from bakerelectronics.com but I am unable to locate the correct wire to connect too and bakerelectronics.com has no idea either but would like to know when I figure it out. LOL

Does any one know how to hook this module up?

 

Sorry can't help you with the bypass module because I'm not sure what the unit is trying to bypass and trying to do. I got no information from the link.

As far as your VATS problem goes the CCM is the unit to focus in on and not the ECM. The CCM controls the VATS and activates the start enable relay. If it is possible to check the key pellet resistance down at the CCM connector, at least you will know if all is good back up to the wheel and switch assembly. If that’s all good, the CCM might very well be bad. Not many go bad so you got to wonder if you are checking all that’s necessary. You say you can read codes which says to me that the CCM seems to have a high level of functionality. I assume that is the only code.

If the engine will not turn over when you turn the key, that the part you have to zero in on and forget about the rest for now. If you can fix that, probably everything will fall into place.

If you just can't find anything, you may need to substitute a CCM for confirmation. Easer said than done. It will obviously have a different key pellet and it will probably have to be bypassed with the correct resistance. But then you will at least know where you are.

I will check my books tonight and see if anything else comes to mind.

 

Unplug the clutch safety switch (gear selector switch if automatic) and jump it. Measure the voltage on the jumper to ground, it should be 12v with ign switch in crank position. If not, you will have to trace 12v from the ign sw to the start enable relay to the clutch safety switch, through the firewall connector to the starter solenoid connection on the starter.